Zend certified PHP/Magento developer

Magento checkout after load refresh and redirect to other URL

M2.4.6-p2. After redirecting to checout, chekout form is loaded and then in same second its like that page is reloaded to other url https://one.elavonpay.com/aflink.php.. how to find in Magento where is this piece of code to remove it.

M2.4.6-p2 is new installation, from old project there left only database and images… everthing else is brand new….

Any ideas?